Siloam Springs's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Siloam Springs is Category C. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Nationally, Siloam Springs ranks above 67% of the 4,875 cities in this dataset for seismic hazard - the 67th percentile.

Siloam Springs by the numbers

The raw figures: peak ground acceleration 0.067g, short-period spectral response 0.142g, 1-second spectral response 0.084g. Among 68 Arkansas cities in this dataset, Siloam Springs ranks 64 for seismic hazard, the 6th percentile within the state. About 20,075 people live in Siloam Springs, Arkansas.

What a retrofit costs in Siloam Springs

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Arkansas. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

Earthquake insurance for a Siloam Springs home

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a Siloam Springs address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Siloam Springs's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.